This invention relates to an infrared thermometer, and more particularly to an infrared probe which is arranged to eliminate the conventional waveguide tube.
Traditional contact-type thermometers, such as mercury and electronic thermometers, are no longer preferred by the users because of their slow reaction and inconvenience. Under the requirements of easy-measure and easy-read, the infrared thermometers the new selection.
Mostly, an infrared thermometer comprises a probe for inserting into the ear of a human body to detect the body temperature. The conventional probe includes an infrared sensor and a waveguide tube adapted to transmit the thermo-wave (radiation) from the ear and eardrum to the infrared sensor.
FIG. 1 shows a cross sectional view of a conventional probe 10 having a hollow conical structure. The probe 10 is positioned to a front end of a thermometer 12. Inside the probe 10, there is an infrared sensor 104 disposed at a bottom end of the probe 10. Facing to a detecting side of the infrared sensor 104, a tubular waveguide 106 is extended from a tip end of the probe 10 to contact with the infrared sensor 104. A temperature sensor 108 is connected to infrared sensor 104 for detecting the temperature and connecting to a calculating unit for calculating the detected temperature.
Conventionally, if the temperature between the infrared sensor and the waveguide is different, the temperature calculation of thermometers contains error. To solve this problem, the waveguide can be made of high conductive metal which is mirrored and gold electroplated.
During the measurement, the probe 10 will insert into the ear and contact therewith. Because the temperature of the ear is higher than the probe 10, heat will transfer from the ear to the probe 10 and then to the waveguide 106 to increase the temperature. The infrared sensor 104 will be affected by this temperature change that results a measurement error.
In order to solve this problem, a tubular pipe 102 is disposed between the probe 10 and the waveguide 106, as shown in FIG. 2. The pipe 102 provides heat isolation between the probe 10 and the waveguide 106. This pipe 102 is made of conductive material which can isolate the sensor from heat. By insulating the heat transfer between the probe 10 and the waveguide 106 with the pipe 102, the temperature measurement error can thus be minimized.
However, once there has a waveguide to transmit the thermo-wave, energy loss can not be avoided and temperature measurement will never reflect the real.